Compressor

Limiter

Compressor with a high ratio setting; Used to suppress dynamic levels of a reproduced sound above a preset limit in order to provide a more constant output level; When the ratio setting exceeds 8:1 the device will function as a limiter.

Anti-Aliasing Filter Slope

Psychoacoustics

Haas Effect

Time frame in which the listener will perceive no change in the sound, except the volume change that occurs when two waveforms are added together; Exists in the range of approximately 0 to 9 milliseconds.

Flanging

Chorusing

An effect that will create the impression that multiple instruments are playing the same part; Created by having several versions of the original dry signal occur at different times and each one being slightly
detuned from the other; Two or more delays each with different time periods (between 20 and 60 milliseconds) can be used to create this effect.

3 Ways to Determining Delay Time

Gated Reverb

Does not decay naturally as the closing of a gate cuts off the trailing reflections; Normally controlled by room size and diffusion; Not as dramatic and smooth sounding as true gating; Very popular effect with drums.

Reverse Effects

Phase Shifting

Taking a particular frequency band and changing the phase relationship of that band with the original signal, creating a comb filtering effect; Cancellations take place in a specific frequency band; Sounds like two instruments playing the same rhythm & gradually shifting out of unison.

Time Based Processor

Delay Units

Hold the signal sent to them for a period of time and then the signal travels to the processor's output; May also be re-routed back through the unit to be delayed again and again, creating multiple repeats (echoes) of the signal.

Delay Modulation Section

Reverb

Created when a sound produced in an enclosed space causes a large number of echoes to build up and then slowly decay as the walls and air absorb the sound; Changes the perceived harmonic structure of a note, but does not alter the pitch.

RT60

The time required for reflections of a direct sound to decay by 60 dB below the level of the direct sound. Reverberation time is either defined for wide band signals or for a one-third octave band centered at 500 or 1,000 Hz.

Reverberation Time

Chamber Reverb

Created with a small, highly reflective room, a speaker, and one or more microphones placed inside; Dry signal is sent into the speaker for the room to reverberate it and microphones pick up the sound.

Reverb Early Reflection Control

Harmonizer

Allow the pitch and timing of signals to be altered by modulating the sampling rate up or down; Frequently used to create the illusion of more sound sources than are actually present, or to correct and/or disguise slight flaws in pitch (tuning).

∞:1

Keying

Anechoic Chamber

Widely used for measuring the acoustic properties of instruments, measuring electro-acoustic devices, testing microphones, and performing psychoacoustic experiments; Designed to completely eliminate reflections of either sound or electromagnetic waves.